"How can you be the party of facts when none of that is true?" Derbyshire asked.
"We are the party that stands up for facts," Donelan replied, before claiming a "lot of people" have called for a meat tax.
"I'm not going to let this go," Derbyshire interrupted and said all of the claims were "untruths".
"They are fiction, they are completely and utterly made up and it's really disrespectful to voters," she said.
"Is this how desperate the Conservative Party is now?" she added.
Donelan said the party was not "in desperation mode". Instead, she said it was in "delivery mode" and continued saying she had heard members of the Labour Party advocate for the policies despite Derbyshire fact checking her.
The Tories are having a terrible time of it. What a shame...